The purpose of this study was to examine under conditions of acute ethanol administration the effect of age on: (1) the kinetics of distribution and elimination of ethanol, (2) posterior pituitary function and free water clearance, (3) psychomotor and cognitive performance. Ethanol concentrations in the blood reach slightly higher levels in older subjects even though standardized amounts are administered to all subjects. This is attributable to the change in body composition (loss of cellular mass) with aging. The rate of ethanol metabolism does not change with age.